Wehr Life Sciences, 506
B.S., 2000, Juniata College, Huntingdon, PA
Ph.D., 2006, Yale University, New Haven, CT
Postdoctoral Fellow 2007-2012, University of California- Santa Cruz, Santa Cruz, CA
The aim of the research in my lab is to elucidate mechanisms that underlie the ability of organisms to successfully develop in the face of environmental challenges. Although much progress has been made in understanding how development proceeds in controlled laboratory settings, it is less clear how development is implemented when that same organism experiences differing environments. My research uses C. elegans to investigate the mechanisms that promote successful development in the face of changing environmental conditions, specifically temperature.
Buffering of chromatin states and gene expression at high temperature
The successful development of an organism relies on the proper implementation of a series of cell fate decisions. Two intertwined aspects of cell fate decisions during development are changes in gene expression and changes in chromatin states. In animals that cannot control their internal temperature, such as C. elegans, differences in molecular kinetics and developmental rates at different temperatures can alter the timing and outcome of developmental fate decisions. Therefore, mechanisms need to be in place to ensure proper gene expression and chromatin states during development at different temperatures. My research group is building on the system I have established, namely that synMuv B transcriptional repressors are necessary to promote proper gene expression, chromatin states and cell fates during C. elegans development at high temperature. In synMuv B mutants changes in chromatin, gene expression, and cell fates result in a compromised intestine and high temperature larval arrest (HTA). Ongoing projects in lab are focused on 1) Elucidating how synMuv B proteins promote proper gene expression at high temp in the SOMA; 2) Determining how synMuv B proteins promote fertility and gene expression in the GERM LINE and 3) Determining how novel proteins promote high temperature arrest in synMuv B mutants.
Buffering oogenesis and sperm function at high temperature
Sensitivity of the germ line to elevated temperature is conserved from worms to humans. For example, loss of fertility in men exposed to high temperature is a known problem in family planning. Additionally increasing temperatures due to global warming could have significant effects on livestock breeding, as many domesticated stocks display decreased fertility during the warm summer months. As a way of investigating the molecular mechanisms that underlie high-temperature sterility and to determine pathways that buffer fertility at high temperature, my lab is studying the natural variation in germline temperature sensitivity in wild-type isolates of C. elegans. The standard C. elegans wild-type strain, N2, demonstrates almost complete sterility at 27°C due mostly to loss of sperm function. Our studies have revealed that wild-type isolates from around the world demonstrate a range of population fertility (from 5%-50%) at 27°C. Sterility of most strains is due to loss of sperm function. An exciting and novel discovery is the identification of an isolate whose sterility appears to be due to loss of oocyte but not sperm function at high temperature. Ongoing studies are using these wild C. elegans strains to determine which aspects of germ cell function are sensitive to temperature. We are investigating if there are differences in gene expression in these different strains, which may underlie their different high-temperature phenotypes. In the long term, we will create recombinant hybrid strains between temperature-sensitive and temperature-insensitive strains. These hybrid strains will enable mapping of loci that are important for buffering fertility at high temperature.
Petrella, L.N.*, Wang, W.*, Spike, C.A., Rechtsteiner, A., Reinke, V., and Strome, S. 2011. synMuv B proteins antagonize germline fate in the intestine and ensure C. elegans survival. Development 138: 1069-1079. (* co-1st authors)
Spencer, W.C., Zeller, G., Watson, J.D., Watkins, K.L., McWhirter, R.D., Petersen, Henz, S.R., Sreedharan, V., Widmer, C., Von Stetina, S., Katz, M., Shaham, S., Petrella, L.N., Strome, S., Jo, J., Reinke, V., Rätsch, G., and D.M. Miller III 2011. A spatial and temporal map of C. elegans gene expression. Genome Research 21: 325-341.
Hudson, A.M.*, Petrella, L.N.*, Tanaka, A.J., and Cooley, L. 2008. Mononuclear muscle cells in Drosophila ovaries revealed by GFP protein traps. Dev Biol 314: 329-40. (*co-1st authors)
Quiñones-Coello, T.A.*, Petrella, L.N.*, Ayers, K.*, Melillo, A., Mazzalupo, S.M., Hudson, A. Wang, S., Castiblanco, C., Buszczak, M., Hoskins, R., and Cooley, L. 2007. Exploring strategies for protein trapping in Drosophila. Genetics 175: 1089-1104. (*co-1st authors)
Petrella, L.N., Smith-Leiker, T., and Cooley, L. 2007. The Ovhts polyprotein is cleaved to produce fusome and ring canal proteins required for Drosophila oogenesis. Development 134: 703-12.
Petrella, L.N., Dorighi, K., Quan, T., and Yuh, P. “Inquiry interpreted for the Biological Sciences: Challenges and Triumphs” 2010, in Astronomical Society of the Pacific Conference Series 436, Learning from Inquiry in Practice, eds. L. Hunter & A. J. Metevier (San Francisco, CA: ASP) 436: 557-561.
Dorighi,K., Petrella, L.N., McCann, S., and Metevier, A.J. “An Inquiry-Based Microbiology Short Course in the SUMS Program at Hartnell College” 2010, in Astronomical Society of the Pacific Conference Series 436, Learning from Inquiry in Practice, eds. L. Hunter & A. J. Metevier (San Francisco, CA: ASP) 436: 203-210.
BIOL 1001 - General Biology 1
Meghan Fealey (Ph.D. student)
Dr. Petrella is currently accepting new Ph.D. students into her lab